Cameras are seriously complicated tools – after all, it takes a ton of complicated work to capture the light reflected by a scene and transfer it into a digital or physical replica. These days, they are smart enough to handle the hardest parts and make our lives easier, so we don’t have to learn everything about them right off the bat when we first get into photography. That said, understanding the different mechanisms of our cameras and how they work together to create our images will help us really master the craft. So today, we’re going to dive into understanding camera aperture.
The idea of “exposure” in photography refers to the amount of light that is used, or the amount of light that is allowed to pass from the world, into the camera, and onto the film or digital sensor. Many people use the analogy of water in a bucket to make it easier to understand.
The amount of light used by the camera is determined by a few different settings, just like the amount of water that flows into a bucket is determined by several factors. The size of the hose used to fill the bucket, and the amount of time that the hose is used for, determine the rate at which the water flows into the bucket; the volume of the bucket determines how much water is needed to fill it, without leaving it partly empty (underexposed) or causing it to overflow (overexposed).
The aperture of your camera is the width of the opening in the lens, through which the light passes; it is the size of the hose in the water analogy. Aperture is described in “f/stop”, which describes the distance between the rim and the opening. Larger f/stops, like f/11 and f/16, describe a small aperture, while smaller f/stops, like f/1.4 and f/2, describe a large aperture. It’s an important part of understanding exposure, and often the first one that we learn about, but its relationship to other factors is what really allows you to find the perfect exposure for a photo.
ISO is the second piece of what we call the “Exposure Triangle”, which determines the perfect level of exposure. It describes the camera’s sensitivity to light, and as a general rule, it’s best to work with the lowest ISO that you can, because making the camera more sensitive to light increases the amount of “noise” in the image. ISO is usually only increased when you can’t get the right balance using the other two legs of the triangle: aperture, which we’ve just discussed, and shutter speed.
The shutter speed refers to how long the camera’s sensor, or the film, is exposed to light. A fast shutter speed means that the shutter will close quickly, and the sensor will only be exposed to a small amount of light; a slow shutter speed means that the shutter will take longer to close, and the sensor will be exposed to light for a longer time. This affects the amount, or lack, of motion blur present in the image, among other things. A faster shutter speed can prevent motion blur from shaky hands or otherwise undesirable blur, but slow shutter speed can convey motion or the passage of time in shots of things like waterfalls.
Depth of Field
Exposure is a big reason why you would adjust your aperture, but it’s not the only thing affected. The depth of field, the blurriness or sharpness of the background or foreground relative to the main subject, can also be changed by using different apertures.
A low f/stop value blurs the background of the scene and puts the focus on the foreground and the subject. This is ideal for portraits of people, photos of pets and animals, or any other type of image where you want the subject to stand out and the background becomes less important.
A high f/stop value makes the whole image sharp, so that you can see the background just as well as the foreground. This is better for landscapes, some types of nature photography, or anything where you want the viewer to see the entire scene.
I know, this can seem like a lot of information to take in at first. You’ll get the hang of it pretty quickly, but if you feel like you need more support, you can always reach out to peers through the Facebook group. There are also photography education resources available to make you feel like a pro behind the camera, in your Lightroom workspace, and anywhere else your photography takes you. The important thing is that you want to improve your photography skills to understand your art better; be patient, have fun, and the rest will follow!
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